pthread_once.h
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/*
* Copyright (C) 2014 René Kijewski <rene.kijewski@fu-berlin.de>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup pthread
* @{
* @file
* @brief Singletons features / single-shot execution.
* @note Do not include this header file directly, but pthread.h.
*/
#ifndef SYS__POSIX__PTHREAD_ONCE__H
#define SYS__POSIX__PTHREAD_ONCE__H
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Datatype to supply to pthread_once().
*/
typedef volatile int pthread_once_t;
/**
* @def PTHREAD_ONCE_INIT
* @brief Initialization for pthread_once_t.
* @details A zeroed out pthread_once_t is initialized.
*/
#define PTHREAD_ONCE_INIT 0
/**
* @brief Helper function that ensures that `init_routine` is called at once.
* @details Calling pthread_once() changes `once_control`.
* For the same `once_control` the supplied `init_routine` won't get called again,
* unless `once_control` is reset to #PTHREAD_ONCE_INIT or zeroed out.
* @param[in,out] once_control Flag to ensure that the `init_routine` is called only once.
* @param[in] init_routine Function to call if `once_control` was not used, yet.
* @returns 0, this invocation cannot fail.
*/
int pthread_once(pthread_once_t *once_control, void (*init_routine)(void));
#ifdef __cplusplus
}
#endif
#endif /* SYS__POSIX__PTHREAD_ONCE__H */
/**
* @}
*/